One question.  I haven't RTFM yet but how does a (VO) quota relate
to space (in SRM 2)?

Say My Dynamic VO comes along, wants some space from Ben.  So
we call him and say "give us space", and Ben, being a friendly
person says "OK <token> is 1 TB".

And MDVO is happy because we write data into the space, and Ben
is happy because if we write too much, the SRM will reject it
(in the Glorious Future of SRM 2.2).

And maybe MDVO goes away, but we still have the SURLs till Ben
goes through the SE shutdown procedure (need to check that - can
the admin make the space read/delete only?)

Isn't that the-same-thing-or-better or am I missing something.

Cheers,
			--jens


-----Original Message-----
From: GRIDPP2: Deployment and support of SRM and local storage
management [mailto:[log in to unmask]]On Behalf Of Ben Waugh
Sent: 13 June 2006 11:56
To: [log in to unmask]
Subject: Re: Quotas for dCache/DPM


Hi Greig,

That is the main reason from my point of view. Currently at UCL-HEP, LCG 
shares a partition with non-grid users. I am quite happy to move away 
from this to have a dedicated LCG partition, but having to have a 
separate partition for each VO is going to mean a lot of shuffling data 
around, causing inconvenience for local non-grid users as well as taking 
up scarce system administrator time. We will have to pick a size for our 
ATLAS partition and then stick with it for the foreseeable future, 
whereas with quotas we could be a bit more flexible and increase the 
available space later if required.

The requirement for a separate partition for each VO also means we have 
to choose between (a) setting up and maintaining extra dedicated pool 
nodes for smaller VOs and (b) withdrawing support for those VOs. As 
UCL-HEP is a small site compared to the main UCL-CENTRAL facility, this 
might have a comparatively small effect on LCG as a whole. However, it 
would be unfortunate if smaller sites were driven out of LCG by the 
increasing hardware and administration required.

The extra flexibility provided by quotas seems to me to be a very strong 
reason for supporting them. It would make administration a lot easier 
and thus allow us to offer a better service.

Cheers,
Ben

Greig A Cowan wrote:
> Hi everyone,
> 
> Can people respond with some examples of why they would like VO quotas in
> dCache or DPM? One reason is that it would allow us to let VO's share disk
> pools/filesystem but prevent them from using up all the space. This would
> mean that we could easily report the used and available space aswell.
> 
> Can people think of other advantages?
> 
> Cheers,
> Greig
> 


-- 
Dr Ben Waugh                                   Tel. +44 (0)20 7679 7223
Dept of Physics and Astronomy                  Internal: 37223
University College London
London WC1E 6BT